Shear grinding mechanism



Sept. 30, 1941. B. sTREzoFF SHEAR GRINDING MECHANISM Filed Oct. l2, 1939 Patented Sept. 30, 1941 UNITI-:D STATE s PA'TQlazN'rV oFFlcE f sHEAn GRINDING. MEoHANIsM Bogoia Strezoi, Minneapolis, Minn. a Application october 12, 1939, Serial No. `293,114 (C1. 51-125) 1 Claim.

This invention relates to grinding and Sharpf ening apparatus and is particularly adaptable for use in connectionrwith the sharpening of the blades of shears or scissors.

One of the objects of my'invention is to provide a shears sharpener in which the blade being sharpened vwillbe held in proper relation to a rotary sharpening wheel so that a regular and properly inclined face is produced at the cutting edge.

Another object of the invention is to provide a Sharpener or grinder wherein the pressure of the blade against the wheel can bevaried at will and wherein such variation is produced through hand manipulation. so that the operator can actually feel the amount of pressure applied.

A further object of the invention is to provide a blade holding means which enablesr quick and simple insertion `and removal of the blade and wherein the blade holder is movable relative to the grinding wheel to further facilitate insertion and removal.

These and other objects andadvantages of the invention will more fully appear `from the following description made in connection with the accompanying drawing, wherein like reference characters refer to the same parts throughout the views, and, in which: a

Fig. 1 is a view in elevation of one embodiment of my invention;

Fig. 2 is a plan viewthereof; a Fig. 3l is Va section taken approximately on the line 33 of Fig. 1;

Fig. 4 is an elevation of another embodiment of the invention; a

Fig. 5 is a side elevation of a blade clamp construction common to both embodiments; and

Fig. 6 is a section taken approximately on the line B--B of Fig. 5.

In Fig. 1 there is shown a bracket B which has an upper lateral extension 'l and a lower lateral extension 8. Threaded vertically through the lower extension 8 is a thumb screw 9 which rotatably carries a clamp element IIJ. The bracket is adapted to be slipped upon the edge of the table or bench II and the thumb screw 9 tightened vto firmly grip the table edge between the clamp element I Il and the lateral extension 1 on the bracket B.

Rotatably supported on and extending upwardly from the upper portion of the bracket B is avertical shaft I2 whose upper end carries a wheel I3 having an upper fiat abrasive surface I4. Adjacent the lower end of the shaft I2 the bracket B is provided with a cut-out Cil l5 within 55 which is located a beveled gear I6 secured to said shaft I2. This gear is relatively small and is adapted to mesh with a larger gear II mounted for rotation with a shaft I8 journalled horizontally in the lower portion of the bracket B. A hand crank I9 is also secured upon said shaft I8 and when it is rotated it will in turn rotate the gears I6 and I'I, the vertical shaft I2 and the rotary wheel I3.

A bracket C is provided at one end with `a partially circular portion 2U which-carries a pair of inwardly turned lugs 2l. The curved bracket end 20 is adapted t0 fit around the upper portion of the main bracket B which is concentric to the vertical shaft I2 as best shown at 22 in Fig. 3. The lugs 2| are adapted to be fitted into appropriate detentsin said rounded upper bracket portion 22. The bracketCextends outwardly in a horizontal direction from the portion 22 of the main bracket B and is provided with anl upwardly turned outer end 23 which is rolled as at 24 to provide a tubular bearing or pivot portion. The two ends of the tubular bearing 24 are adapted to receive arms '25 which extend outwardly from theadjacent's'ides of a` substantially U-shaped blade clamp 26 at one end of said clamp. The clamp 2E is preferably'of sheet metal and the extending arms 25 are preferably rounded at their ends sothat they will better fit the tubular turned end'24 on'the bracket C. 'The blade clamp 28 is adapted to'move in pivotal relationship to said-bracket C. The blade clamp, as stated above, is`sheet metal and preferably resilient so that itwill assume the shape shown in Figs. 1 and 6 when no external force is applied thereto. It is of vgenerally inverted U- shape and the body of the clamp is tilted at an angle to the vertical so that a blade held therein will be retained in proper relation to bevel the cutting edge of the shears blade. Central portions of the clamp 26 are partially cut out and bent upwardly to provide levers or grips 21 so that the clamp can be opened slightly by pressure on said levers toward each other. The clamp is pressed open in order to facilitate insertion of a blade such as the blade 28 shown in Figs. l and 2. To reenforce the sheet metal clamp 26 I provide a wire spring element 29 which, as shown, extends along opposite outer sides of clamp 26 and over said clamp as at 29a. This spring is retained upon the clamp by small tongues 3l) which preferably are punched out of the metal sheet of the clamp itself.

As shown in Fig. 2 the bracket C is curved slightly at the outer end of the horizontal portion thereof so that the blade clamp 26 Will not pass over the center of the wheel at the end of the vertical shaft l2. Furthermore, the tilt- 'ing of the blade clamp above described is such that the upper edge of the clamp is nearest the end of said shaft l2 so that the clam-prwill strike against the shaft as it is swung toward the center of the abrasive wheel and the edge of the blade heldin the clamp will not be injured. There is no pivotal swinging movement towardY and away from the vertical shaft I2 in the. structure shown but the clamp is relatively loosely supported so that the blade edge will lie flat against t'he abrasive surface i4 and it is entirely possible at times to bring the clamp intoycontact with' the vertical shaft l2.

the grinding wheel are provided for the reason that some might find it more convenient to work on a device with a wheel in one or the other of the two positions.

From the foregoing description it will be seen that I have provided a simply constructed yet ecient apparatus for grinding and sharpening the blades of shears wherein the blade can be easily slipped into the blade clamp either .longitudinally through theV open, end ,of the clamp or it may be slipped intothe openbottom of the clamp after the clamp has been swung away fromrthe grinding wheel to some extent. The

' clamp can be pressed with varying degrees of When the device is operated it maybeuset in motion by turning of the crank` vI9 with either; t

hand leaving the other hand free to manipulate the blade holding clamp 26 as desired.` It'is contemplated that the jclamp bracket C can be curved at its outer end to bring the yclarnp 25 on either side ofthevertical shaft I2. t In Fig. 4 thereis shown an embodiment Wherein the; abrasive wheelis placed vertically rather than horizontally as in the embodimentk illustrated in Figs; 1 and 2; In this embodiment the mainbracket D extends vertically from the table Y or bench Il a greater extent than therbracket B Yin the other form and Ythe abrasive wheel 3| Y which is mounted'in a vertical plane is supported by a horizontal shaft 32 which is journal'led in the vtop of said bracket D. yA small pinion 33 meshes with `al largergear'34 provided with a crank 35.' The gear 34 and crank 35Vare mounted on a horizontal stubshaft 36 whichis journalled in the main bracket D. As shown a detachable screw clamp -is formed at the bottom of the bracket D as in the other embodiment described.

A blade clamp 31 which is constructed the same as the'clarnp 246 in Fig. 1 is Vmounted relative to the abrasive surface of the wheel 3l to produce grinding or sharpeningjof a shears bladein eX- ac-tly the same manner as before described. There is a small 'bracket'S'L however, which is different from the bracket Cshown in Fig. 1J` and it comprises merely a right-angled element having `on@ end rigidly secured as by screws Vto. the main bracket D and one arm of which extends outwardly adjacent the edge of the wheel 3 l. The outwardly extend-ingA arm of the bracket 3l is provided with azsubstantially cylindrically turned portion 38 similar to the end24'on the bracket C, andv the-blade clamp 3.6 is mounted on the vbracket 3'1 in the same manner as its pivotal oon- Vnection with bracket C. The `general operation of each of the two forms of the invention is the same and the horizontal and vertical positions of force to make a heavy or a light cut on the blade edge and it is preferred that the brackets C or 3l be resilient to some extent so that there will beproper contact between the cutting edge of the blade and the grinding wheel. VIt is a relatively compact device which can be quickly set upon arr/edge of a table or bench andit can vbe just asgreadily detached and stored.. While the blade clamp is relatively flexibly mounted it. willbecause of its tilted'positionprcduce a proper anduniform angularity at thegcuttingedge--so that upon successive sharpenings thisv angle will be maintained. Due tov the gear arrangement shownl the device can be hand operated and: the grinding wheel will rotate with vconsiderable speed. For that reason a relatively ne abrasive face can be provided on the wheel for the production of a smooth and satisfactory shearsV edge. It will, `of course,y be .understood that various changes may be made in the form, details, arrangement and proportions of the various parts lthroughout theviews without departing from the scope of my invention. What is claimed is:A L i In a shears Sharpener and the like, a rotary sharpening wheel havingv afflat vworking face, a bracket. supporting said wheel `for rotation, a work clamp support connectedtosaid bracket and having its outer end terminating adjacent the edge of said Wheel, said outer; end having an aperture therein onan axis parallel 'to the Yworking face of said wheel, and a'work clamp compris-.- ing an elongated jaw member adapted toV lie across and closelyV adjacent the working face of said wheel, said jaw member having a pair ,of resilient arms extending outwardlyfrom an end thereof, said arms having their endsturned inwardly toward each Votherand resting inthe aperture in said clamp supportyand said jaw.` member having cooperating relatively; thin jaw portions whose longitudinal edges vare flared apart to facilitate insertion of `a Ashears blade therebetween. Y l Y BOGOIA vS'IREZOFF 

